1. Field of the Invention
The invention relates to vacuum cleaners having cyclonic separation systems, and in particular to a debris collection container and filter housing removable from a main housing. In one of its aspects, the invention relates to a bottom discharge debris collection container removable from a main housing independent of a filter housing. In another of its aspects, the invention relates to a filter housing associated with a filter assembly where the filter housing is jointly removable from the main housing together with the filter assembly. In yet another of its aspects, the invention relates to an interlock for a vacuum cleaner to prevent removal of the filter assembly from the filter housing while the filter housing is mounted to the main housing.
2. Description of the Related Art
Vacuum cleaners employing cyclone separators are well-known in the art. Cyclone separator designs commonly employ frusto-conical shaped separators, while others use high-speed rotational motion of the air/dirt in a cylindrical separator to separate the dirt by centrifugal force. Typically, working air enters and exits at an upper portion of the cyclone separator while the bottom portion of the cyclone separator is used to collect debris. It is further known to employ multiple serial cyclone separators to improve the collection of fine debris particles that may not be collected by a single separator. Furthermore, in an effort to reduce weight, the motor/fan assembly that creates the working air flow is typically placed at the bottom of the handle, below the cyclone separator. This arrangement therefore, requires a tortuous air path from the top of the cyclone assembly, down the handle to the inlet of the motor/fan assembly. This creates a long air path with multiple parts which may allow for air leaks and generally negatively impacting airflow and, necessarily, cleaning performance.
BISSELL Homecare, Inc. presently manufactures and sells in the United States a vacuum cleaner with cyclonic dirt separation and a bottom discharge debris collection container. The debris collection container is located beneath the cyclone separator and further has a filter located beneath the debris collection container and between the debris collection container and a suction motor inlet. The air flowing through the cyclone separator passes through an annular cylindrical cage to a hollow standpipe that extends through the debris collection container and to a filter housing that is in communication with the suction motor inlet. A filter secured within the filter housing removes fine particles in the airstream that passes from the cyclone separator to the suction motor inlet. The filter housing is connected to the debris collection container whereby both the debris collection container and the filter housing are selectively removable together from the main housing. The cyclone separator, debris collection container, and filter are further disclosed in U.S. Application Publication No. 20070084158, which is incorporated herein by reference in its entirety.
To ensure efficient operation of a vacuum cleaner, clogged filters must be cleaned or replaced periodically. Configuring a debris collection container and filter housing to be separately removable from a main housing can increase the visibility of a pre-motor filter assembly to an end user. Increased visibility, in turn, can lead to a higher probability of adequate filter maintenance. With the increased chance of filter removal for replacement or cleaning, however, the risk of inadvertent vacuum cleaner operation without a pre-motor filter also increases. This is undesirable because any fine dust remaining in the working airstream can be ingested by the fan/motor assembly and can lead to premature fan/motor wear or failure. Therefore, it is desirable to implement a design that alleviates this concern by preventing filter removal while the filter housing is mounted to the main housing.
U.S. Pat. No. 6,829,805 to Yang discloses a canister vacuum cleaner that has an exhaust filter cover that can be locked to one side of the main body of a vacuum cleaner. A filter is locked within the filter cover in a bayonet-style mounting arrangement. The outer peripheral surface of the filter is fitted into a mounting ring of the filter cover, and the filter is rotated to bring protrusions formed thereon into engagement with grooves on the filter cover.
U.S. Pat. No. 6,868,579 to Yang discloses a canister vacuum cleaner that has an exhaust filter cover that can be locked to a motor housing of the vacuum cleaner. The locking arrangement comprises protrusions that protrude radially inwardly from an inner end of the filter cover and that are received by grooves on the motor housing and locked therein by rotation of the filter cover relative to the motor housing.